'Healthy' diet = weight gain

Diets high in fat do not appear to be the primary cause of the high prevalence of excess body fat in our society, and reductions in fat will not be a solution.
DR WALTER WILLETT

Part 1: How a 'healthy diet' fattens

The prevailing wisdom over the past several years has been that fat makes you fat, and that if you simply stop eating fat, you'll lose weight without even trying. A typical example is: 'Fats are a concentrated form of energy, providing 9 calories per gram, compared to 4 calories per gram for both carbohydrates and protein. That is why high fat diets can lead to weight gain much easier than lower fat diets: it's easy to eat foods packed with calories and not realize you have eaten too much'

That may sound plausible but, I'm sorry, it's nonsense, and cutting fat out doesn't work - but you have probably discovered that for yourself.

In a supplement to the American Journal of Clinical Nutrition in 1998 entitled 'Is Dietary Fat a Major Determinant of Body Fat?',[1] Professor Walter Willett of Harvard University School of Medicine confirmed what some of us have known for years - that if there is a weight loss associated with changing to a low-fat dietary regime, it is statistically small and the results are highly short-lived - when he found: '. . .fat consumption within the range of 18-40% of energy appears to have little if any effect on body fatness.'

So cutting fats doesn't work. Dr Willett continued: 'Moreover, . . . a substantial decline in the percentage of energy from fat consumed during the past two decades has corresponded with a massive increase in obesity.'

This has become blindingly obvious. Could cutting fat be the cause of obesity? Dr Willett concluded: 'Diets high in fat do not appear to be the primary cause of the high prevalence of excess body fat in our society, and reductions in fat will not be a solution.'

He's quite right. But there is more:

As fat in the diet is a significant contributor to being satisfied with a meal, low-fat diets often leave dieters very hungry. Those who tell you that, to maintain a normal weight you must eat a low-fat diet, want you to live your life hungry most of the time. And you simply can't do it. Your body is not designed to operate in this way and it rebels. No other animal on this planet counts the percentage of fat calories (or any other calories) in its diet; there is no need for us to, either.